What are the metering light standards in your state? All of the far west states have a standard 3 signal light (where the yellow is sometimes used for a 2nd car to pass through the meter, albeit rarely), while states like Arizona, Nevada or Florida only use two (green/red).
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fops.fhwa.dot.gov%2Ffreewaymgmt%2Fpublications%2Ffrwy_mgmt_handbook%2Frevision%2Fjan2011%2Fmgdlaneschp8%2Fimages%2Ffig17.jpg&hash=c13b3e3a67df427a1a80f286a81d78ae8c35e2fb)
Similarily, how is the approach to a meter light handled?
Oregon uses standard size LED signs:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.kezi.com%2Fwp-content%2Fuploads%2F2013%2F10%2F10-11-BELTLINE-RAMP-METER-PIC.jpg&hash=860206d5f43535065925bd26d061da4d6b3243eb)
Northern California uses a pedestrian signal mount.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.dot.ca.gov%2Fctjournal%2F2009-2%2Fimages_jpg%2Fdelivery_meter_on.jpg&hash=21a9dce01b496ed1fd430a3123b1e48a280a071e)
San Diego uses the standard traffic light warning sign with a yellow flashing light above it and 'RAMP METER' black on yellow below the sign.
Washington follows more vanilla MUTCD with these:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fops.fhwa.dot.gov%2Fpublications%2Framp_mgmt_handbook%2Fmanual%2Fimages%2Ffigure5_3_7a.jpg&hash=7f4d9e4096916dcc35daf1950b87dc80a5ae89ef)
PA uses 2 lights (Red/Green).
NJ's one and only installation used Red/Green as well (it was only in use for a short time, then the ramp was reconstructed and the ramp light eliminated).
Chicago has plenty of them along the Edens, Kennedy, Eisenhower, and Ryan Expressways.
Edens between the Junction and Dempster Street:
https://maps.google.com/maps?hl=en&ll=41.976386,-87.74585&spn=0.009204,0.021136&t=m&z=16&layer=c&cbll=41.976287,-87.745765&panoid=RcVr1T0QoOmzUntIH5f_1A&cbp=12,321.9,,0,7.22
https://maps.google.com/maps?hl=en&ll=41.976689,-87.746258&spn=0.009268,0.021136&t=m&z=16&layer=c&cbll=41.976752,-87.74635&panoid=sZN8sx8ijVdbGw0b6Mx8iw&cbp=12,318.95,,0,11.97
Kennedy between the Circle and Cumberland Avenue:
https://maps.google.com/maps?hl=en&ll=41.953443,-87.731058&spn=0.001159,0.002642&t=h&z=19&layer=c&cbll=41.953443,-87.731058&panoid=8BQz1vIJZKA87j3NaqM77g&cbp=12,136.53,,0,7.4
https://maps.google.com/maps?hl=en&ll=41.952678,-87.729591&spn=0.001159,0.002642&t=h&z=19&layer=c&cbll=41.952724,-87.729694&panoid=05fC9sDa3Ke2Y9SJCaP9Ig&cbp=12,126.57,,0,8.5
Eisenhower between the Circle and North Avenue:
https://maps.google.com/maps?hl=en&ll=41.873743,-87.805178&spn=0.00116,0.002642&t=h&z=19&layer=c&cbll=41.873764,-87.805392&panoid=c1oePa_Jr8cONSa8iqCDOA&cbp=12,282.39,,0,2.65
https://maps.google.com/maps?hl=en&ll=41.873851,-87.806326&spn=0.00116,0.002642&t=h&z=19&layer=c&cbll=41.873851,-87.806326&panoid=qRp2NJO7JGeRmXBW7hU4IA&cbp=12,282.28,,0,4.39
Ryan between the Circle and the Split:
https://maps.google.com/maps?hl=en&ll=41.751787,-87.624689&spn=0.001644,0.002642&t=h&z=19&layer=c&cbll=41.751891,-87.624702&panoid=aO3scM9sJ_Z2hedFKQXyTg&cbp=12,9.33,,0,11.97
https://maps.google.com/maps?hl=en&ll=41.752349,-87.62473&spn=0.001644,0.002642&t=h&z=19&layer=c&cbll=41.752349,-87.62473&panoid=OAIbrMhfF8KoZUoFS7v1VQ&cbp=12,6.9,,0,17.54
I-57, the Stevenson Expressway, and the Calumet Expressway (aka Bishop Ford) do not have them.
All are of the red/green variety, and some of them are broken or turned the wrong way. The advance warning signage is either "RAMP METER AHEAD" or the signal ahead symbol. They also have one of two signs at the signals themselves, "STOP HERE ON RED" with the arrow, or "WAIT HERE FOR GREEN", again with an arrow.
Quote from: jeffandnicole on March 10, 2014, 10:33:08 AM
NJ's one and only installation used Red/Green as well (it was only in use for a short time, then the ramp was reconstructed and the ramp light eliminated).
New Jersey had a ramp meter? Where and when was this located?
Leaving Harrahs in Atlantic City, approaching 87 South. This ( http://goo.gl/maps/AeN69 ) is the best picture I can grab from Google Maps. The 2 lights are now in the middle of the island separating incoming and outgoing traffic. Before this particular intersection/interchange was redesigned, the ramp entering 87 South went thru those two lights.
As you see in GMSV, the ramp was moved, but the meter lights are still there. They're not in operation, and due to the angles of the roadway, one could easily pass by them without noticing them.
From what I remember, the meter operated a few years at most, and the light sequence had no rhyme or reason to it.
Colorado is R-Y-G for the upper signal head and R-G for the lower head pointing inward. The yellow is only used when the meter is first turning on in the morning and flashes yellow for a minute before going to R-G. The meters are dark when not in use.
The approach is a standard signal ahead sign with a "when flashing" plaque underneath and beacon above.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.mesalek.com%2Fcolo%2Fpicts%2Fi25_evansmtr.jpg&hash=6e6755ec4c9361170708613228ea84bb1498724b)
Do they still use 12-8-8 heads?
Ramp metering seems like it would make it difficult to merge into freeways because it shortens the amount of time you have to pick up speed.
It can do that, Scott, depending on how far down the ramp the meter is placed. At the same time, though, they do help on both the ramp and especially the freeway mainline because they break up the often-huge platoons that are trying to merge all at the same time. MnDOT has for decades documented a reduction in crashes and increases in capacity and freeway speed with ramp metering.
Regarding standards, MnDOT standard is for two signalheads per side, with the lower signalhead angled towards the 1st car in line. 3-lens signals (don't recall if they're 8-inch or 12-inch, but they're all the same size). 1 car per green. Here's a photo from an associate of mine:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm4.staticflickr.com%2F3534%2F3240217477_491e862187_z_d.jpg&hash=f4203f23e81c40b6bc9c8be199b02623b294b2b2) (http://www.flickr.com/photos/mulad/3240217477/)
Quote from: Scott5114 on March 11, 2014, 08:25:22 AM
Do they still use 12-8-8 heads?
Ramp metering seems like it would make it difficult to merge into freeways because it shortens the amount of time you have to pick up speed.
It does. IMHO, they're worthless pieces of junk. One should be at freeway speed before the end of the ramp (60-75 mph).
Quote from: Brandon on March 11, 2014, 12:03:49 PM
It does. IMHO, they're worthless pieces of junk. One should be at freeway speed before the end of the ramp (60-75 mph).
place them far enough back and they make a lot of sense at preventing the congestion from spilling onto the freeway itself.
Quote from: Brandon on March 11, 2014, 12:03:49 PM
Quote from: Scott5114 on March 11, 2014, 08:25:22 AM
Do they still use 12-8-8 heads?
Ramp metering seems like it would make it difficult to merge into freeways because it shortens the amount of time you have to pick up speed.
It does. IMHO, they're worthless pieces of junk. One should be at freeway speed before the end of the ramp (60-75 mph).
Plenty of ramps around where the driver merges into the travel lanes the first chance they get, while going about half the speed limit. The lack of a meter light doesn't stop timid drivers from incorrectly entering a highway.
Quote from: jeffandnicole on March 11, 2014, 12:50:44 PM
Plenty of ramps around where the driver merges into the travel lanes the first chance they get, while going about half the speed limit. The lack of a meter light doesn't stop timid drivers from incorrectly entering a highway.
not to mention that this person will immediately merge into the leftmost lane, still doing ~50.
this has nothing to do with the efficiency of ramp meters. it has to do with the fact that this isn't an $800-plus-two-points ticket.
In heavy traffic, they're good. In moderate traffic, they're alright as long as there is sufficient space for vehicles to speed up to 50 MPH before forcing to merge.
Something no else seems to enjoy...In Washington, we use dotted lines to keep the general public in their place:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fr0wxvmw.png&hash=32d6b0cc20b211638c2f10859ef979e92ad4fce5)
You really only see that where the ramps are metered, which saddens me because I like places like Hawaii's method of placing directional-dotted lines whenever a lane begins or ends (http://goo.gl/xxOAM3). Looks much more interesting in my opinion.
Quote from: Scott5114 on March 11, 2014, 08:25:22 AM
Ramp metering seems like it would make it difficult to merge into freeways because it shortens the amount of time you have to pick up speed.
Here they're only used when traffic is heavy, so I suppose that isn't a huge concern. It just spaces out the traffic trying to merge. They must think it works, the system's been expanded in the last few years.
Regarding layout, we have a red-green system with the yellow diamond "ramp metered when flashing" signs.
Twin Cities ramp meters are three-section, 8-8-8 heads. The yellow is used as a brief transition from green to red, not to allow a second vehicle (signage states "One Vehicle Per Green"). During non-metered hours, the yellow lights flash. A standard pictorial SIGNAL AHEAD sign in advance of the meter signals has a yellow flashing light that flashes during the time the meters are active.
Quote from: jake on March 11, 2014, 07:15:39 PM
Something no else seems to enjoy...In Washington, we use dotted lines to keep the general public in their place:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fr0wxvmw.png&hash=32d6b0cc20b211638c2f10859ef979e92ad4fce5)
You really only see that where the ramps are metered, which saddens me because I much places like Hawaii's method of placing directional-dotted lines whenever a lane begins or ends (http://goo.gl/xxOAM3). Looks much more interesting in my opinion.
PennDOT does this for the ramp meters on I-476.
WisDOT's ramp metering is very similar to others mentioned. All new installations have a 12-12-12 signal mounted at typical signal height, aimed upstream and a 8-8 signal mounted roughly at 5-ft for the vehicle at the stop line. Older installations have a 12-8-8 and the 8-8 signals. In special geometric situations, they'll just have a 12-12-12 signal for each lane mounted overhead (always horizontally-oriented), downstream of the stop bar for the regular lanes, but a typical pole-mount for the HOV lane. Most installations also have a 12-in enforcement light mounted to the backside of the pole
Older WisDOT meter (https://www.google.com/maps?ll=43.031262,-87.987848&spn=0.000008,0.008256&t=m&z=18&layer=c&cbll=43.031262,-87.987848&panoid=EE9cQlV_Onn3saW-SxOrvg&cbp=12,220.4,,0,1.46)
Newer WisDOT meter with 12-12-12 signal (https://www.google.com/maps?ll=43.044864,-89.470519&spn=0.000004,0.004128&t=m&z=19&layer=c&cbll=43.044792,-89.470371&panoid=d9ruS1QsTzP6pjIpf2RsYg&cbp=12,123.83,,0,8.36)
Overhead + HOV meter (https://www.google.com/maps?ll=43.035272,-89.406894&spn=0.000004,0.004128&t=m&z=19&layer=c&cbll=43.035414,-89.406712&panoid=RDMh6-ntsnig3U5dsVy5lQ&cbp=12,219.68,,0,7.84)
When not in use, they rest in green. They have a yellow indication wired (as stated in the standard specs), but I have never seen them used. I asked around at the state traffic op's office (STOC) and no one seemed to know what the yellow was used for (many didn't even know it was there :banghead: ) So much for the right hand knowing what the left hand is doing. :no:
Advanced warning is almost identical to what KEK shows for Washington, except replace the plaque below the diamond with another 12-in amber signal. When the meter is active, both lights flash simultaneously.
WisDOT Meter Warning assembly (https://www.google.com/maps?ll=43.045852,-89.473214&spn=0.000008,0.008256&t=m&z=18&layer=c&cbll=43.045899,-89.473336&panoid=D84VwDAhvztm2D9gWmf5Hg&cbp=12,120.15,,0,7.95)
^^ the yellow is used when metering begins for that time period to warn it is no longer solid green.
Quote from: Big John on March 12, 2014, 05:13:28 PM
^^ the yellow is used when metering begins for that time period to warn it is no longer solid green.
Interesting...makes sense. I've never been around at the exact time when metering started, only well-before or well-after.
Here is Georgia's warning sign (it lights up when the meters are on)
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fmatchbin-assets.s3.amazonaws.com%2Fpublic%2Fsites%2F624%2Fassets%2Framp_meters_on_03.jpg&hash=25d721f5bc8f12db0c8f23dcd9e3f5e033c8c111)
And Pennsylvania's
I-476 at US 30 (https://www.google.com/maps/@40.037301,-75.359652,3a,75y,224.45h,80.11t/data=!3m4!1e1!3m2!1sT8uTVaWm-kb33k50RsyJPw!2e0)
Quote from: jake on March 11, 2014, 07:15:39 PM
Something no else seems to enjoy...In Washington, we use dotted lines to keep the general public in their place:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fr0wxvmw.png&hash=32d6b0cc20b211638c2f10859ef979e92ad4fce5)
You really only see that where the ramps are metered, which saddens me because I like places like Hawaii's method of placing directional-dotted lines whenever a lane begins or ends (http://goo.gl/xxOAM3). Looks much more interesting in my opinion.
In the San Diego area, they use solid white lines on ramps to mark off the HOV merge lanes:
https://www.google.com/maps/place/Carlsbad,+CA/@33.1228426,-117.3216691,151m/data=!3m1!1e3!4m2!3m1!1s0x80dc73453f3bee59:0xa4cb5592fcf65d2f
Many of the metering lights in the Los Angeles area have an 8-8-8 on top with an 8-8 on bottom.
Here's and example at I-10 westbound at Overland: http://goo.gl/maps/xjRTk
The typical metering operation is red-green-red-green, but similar to Wisconsin, the yellow is used only when transitioning from solid green to metering operation. I guess the authorities felt that because the yellow was rare, it only needed to be shown on the upper signals.
I don't know about the operation today, but back in the late 90's when this was on my commute, the meter light on the southbound on-ramp from La Cienega to the 405 freeway south (just north of Florence) had meters off during morning rush, solid green around noon, and then red-green rapid metering during the afternoon rush.
Up here in northern California, metering lights are usually 12-12-12 on top and 8-8-8 on the bottom. Around here, the yellow light is used when 2 cars are allowed per green (signal cycles red-green-yellow-red-green-yellow-red etc). While the 2-cars-per-green is not typical, it is used on some higher volume ramps like from CA-17 to southbound CA-85 during the evening commute.
If a major holiday falls on a weekday, metering lights are still activated but are always green.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.texasfreeway.com%2FDallas%2Fphotos%2Fus75%2Fimages%2Fcentral_looking_south_at%2520walnut_hill_10-june-1990_lres.jpg&hash=74195284c4cd42617b7cbc8bd29c25f091c86fc0)
IINM, the only ramp meters I ever saw were in Dallas along US 75-N. Central Expwy. From what I remember, they didn't work at all or only sometimes, but were largely ignored. As this pic (looking SB at the old-style Walnut Hill exit) shows, if they were supposed to help traffic on Central, it was definitely a too-little-too-late situation. So, if there ever were 'standards', they probably went out the window or were laughed at by the time I first started seeing them (late 1960s).
The meters weren't replaced when Central was redone between 1989 and 1999.
Quote from: Scott5114 on March 11, 2014, 08:25:22 AM
Do they still use 12-8-8 heads?
Colorado switched from 12-8-8 to 12-12-12 with their most recent installations in the last year.
Nevada uses the red/green setup with 12-12 signal heads. At the beginning of the ramp, there is the pedestrian-style "Meter On" display that indicates the ramp meter is active (flashing in Vegas, steady on in Reno's few installations)--a couple newer ramp meters in the Vegas area also include the MUTCD standard warning sign with single flashing beacon, to maintain that compliance.
The ramp meters are almost always mounted with only one overhead signal head per lane. Nevada also does staggered metering, such that the lanes alternate in the release of vehicles. This provides the interesting case of no backup/redundant display in case the signal head or section fails, which I think could be an issue. Interestingly, the seemingly permanent installations in Reno using two signal heads per lane (high and low side-mount signal heads) were eventually replaced with single overhead signal heads per lane.
Quote from: BrianP on June 15, 2021, 01:01:32 PM
I-270 RAMP METER TESTING BEGINS AS PART OF INNOVATIVE CONGESTION MANAGEMENT PROJECT (https://www.roads.maryland.gov/mdotsha/pages/pressreleasedetails.aspx?newsId=3923&PageId=818)QuoteThe Maryland Department of Transportation State Highway Administration (MDOT SHA) is expected to activate and test a new ramp metering system on the ramp from northbound MD 118 to southbound I-270, in the Germantown area of Montgomery County on Wednesday, June 23. This will be the first location activated in the new ramp metering system that will eventually include 22 northbound and 23 southbound I-270 ramps.
QuoteThis single location will be activated as a flashing yellow signal on or about June 16, before becoming fully operational on June 23. MDOT SHA is testing the system at this single location for one week and will then deactivate it until the entire southbound I-270 ramp metering system is activated later this year. The northbound I-270 ramp metering system is expected to be activated in 2022.
QuoteThe signal will allow one car at a time to go from each lane, optimizing traffic flow onto I-270.
How do you allow just one car to go at a time?:
Maryland is joining the states that provide for ramp metering as part of a larger I-270 project.
One thing that baffles me is that the video seems to suggest that once the project is functional, "when ramp metering is not in operation, the advanced beacon will be dark and the ramp meter signal will flash yellow." Is this a common operation for ramp meters? I am used to the flashing beacon being on to warn drivers to be watchful for the red and green stop and go lights. I am also used to a flashing yellow indication on the ramp meter as a warning that the meter will be turning on soon. But in times of light traffic, ramp meters are just typically dark [kind of like HAWK signals]. It would seem to me that if the flashing yellow is used as a warning that you may have to stop, it should not be on when the meter is not operating.
Quote from: Milepost61 on March 16, 2014, 12:01:56 AM
Quote from: Scott5114 on March 11, 2014, 08:25:22 AM
Do they still use 12-8-8 heads?
Colorado switched from 12-8-8 to 12-12-12 with their most recent installations in the last year.
Which is great for collecting signals, as CO has a lot of 12-8-8 heads that get discarded (if the scrapyard doesn't get them, they go on EBay a lot of the time)
Quote from: mrsman on June 15, 2021, 01:54:00 PM
Maryland is joining the states that provide for ramp metering as part of a larger I-270 project.
One thing that baffles me is that the video seems to suggest that once the project is functional, "when ramp metering is not in operation, the advanced beacon will be dark and the ramp meter signal will flash yellow." Is this a common operation for ramp meters? I am used to the flashing beacon being on to warn drivers to be watchful for the red and green stop and go lights. I am also used to a flashing yellow indication on the ramp meter as a warning that the meter will be turning on soon. But in times of light traffic, ramp meters are just typically dark [kind of like HAWK signals]. It would seem to me that if the flashing yellow is used as a warning that you may have to stop, it should not be on when the meter is not operating.
That's something I haven't seen before either.
Interestingly, the 2009 MUTCD's chapter on ramp metering doesn't disallow this. The only mention in the entire chapter about their operation is an option statement that allows the meter signal to be placed in dark mode (no indications displayed) when metering is not in use. So I guess the flashing yellow is allowable and could be analogous to flashing yellow used at older fire station or pedestrian crossing signals, in a "proceed with caution" context.
But I'm with you that I don't really like the idea of a flashing yellow in this context–probably because I've never encountered that before and everywhere I've seen a ramp meter uses the dark mode. But if practically every other state uses dark mode for non-functioning ramp meters, why can't MD get on board? I'd be curious if MD uses dark mode for any other type of signal (like HAWKs), and if not then maybe this is an effort to avoid displaying a dark signal...?
Quote from: roadfro on March 16, 2014, 04:22:09 PM
Nevada uses the red/green setup with 12-12 signal heads. At the beginning of the ramp, there is the pedestrian-style "Meter On" display that indicates the ramp meter is active (flashing in Vegas, steady on in Reno's few installations)--a couple newer ramp meters in the Vegas area also include the MUTCD standard warning sign with single flashing beacon, to maintain that compliance.
Updating myself from seven years ago. Nevada now installs the standard MUTCD warning sign ("ramp metered when flashing") and single yellow beacon to indicate when a meter is operating, and no longer regularly installs the pedestrian-style "meter on" display (although in some recent instances in Vegas, both were installed). I believe this is based on previous FHWA feedback or interpretation on those ped head-style devices. Those still in operation in the Vegas area no longer flash when operating and are steady on, while all instances in Reno have been replaced with standard sign and beacon.
Utah uses full red/yellow/green, 12-12-12 signal heads for the vast majority of its ramp meters, though there are a small handful of older red/green 12-12s still standing. For multilane ramps, the meter lights are overhead with no side signals (typical example (https://goo.gl/maps/QqfC8YPRAP5295bcA)), though sometimes they'll have additional signals to the side (example (https://goo.gl/maps/a1Sro82rmvNWtg3VA)). Single-lane ramps will have one pole to the side, with two signal heads - one facing traffic immediately next to the post and another facing approaching traffic (typical example here (https://goo.gl/maps/MJSAE5qLMCRt1TNP7)).
At most of them, the yellow light is only used when the meter is in the process of activating from dark mode. However, some of the meters allow 2 cars per green instead of the usual 1 - in these cases, the yellow light is used like a normal yellow light. Older R/G meters never allow more than 1 car per green, and they activate by turning on both the red and green lights for several seconds.
The "ramp metered when flashing" sign with alternating flashing beacons on either side (example (https://goo.gl/maps/S7r2ShPbECfUPzan8)) is the usual warning sign now. The old standard was a yellow "metering when flashing" along a variant of the MUTCD traffic signal warning sign (W3-3) with only the red and green, accompanied by a pair of alternating flashing beacons (example (https://goo.gl/maps/y5tjrMxpAb32TXD68)), although some ramps only had the signal-ahead sign (https://goo.gl/maps/Jt9Bkp729dsAJJzFA) and some just had the text-only sign (https://goo.gl/maps/Nm2a1XxKeNR5rkPE9). Not many of those are left.
I'm 90% sure I have seen one of the pedestrian-style "METER ON" signs somewhere in the SLC/Davis County area, but this was probably 10-15 years ago and I cannot figure out where the hell it was. It's almost certainly gone now given multiple reconstruction and resigning projects have occurred in this area since then.
I don't know what the setup was for CT's only extinct ramp meter, at the on-ramp from CT 17 to CT 9 north in Middletown.
There was at least a small R-G signal.
In defense of ramp meters.
BC only ever had one ramp meter which has been gone for almost 10 years and this (https://www.google.com/maps/@49.2283014,-122.8209627,3a,51.5y,256.62h,85.01t/data=!3m7!1e1!3m5!1sllEhA1BbBGpakkN6K7UVnA!2e0!5s20120701T000000!7i13312!8i6656?hl=en-US) is what it looked like.
The new Mountain Highway Interchange in North Vancouver, which is nearing completion, is supposed to get a ramp meter so it will be interesting to see if they keep the same standard.
I think it makes the most sense to have the signal flash yellow, (what MN does). In WI the signals stay green, Which seems dangerous to me, and in other states, the dark indication seems confusing.
iPhone
Ontario has 8-8-8 signals.
(https://i.imgur.com/b4Aitlx.png)
Quote from: andrepoiy on June 17, 2021, 07:00:47 PM
Ontario has 8-8-8 signals.
(https://i.imgur.com/b4Aitlx.png)
Could you share a Google Maps link? From here, they look a lot like 12-12-12.
Quote from: jakeroot on June 17, 2021, 07:53:44 PM
Quote from: andrepoiy on June 17, 2021, 07:00:47 PM
Ontario has 8-8-8 signals.
(https://i.imgur.com/b4Aitlx.png)
Could you share a Google Maps link? From here, they look a lot like 12-12-12.
You're right, they changed them to 12-12-12. I now see the difference. (If you click to an older Streetview picture it was indeed 8-8-8)
https://goo.gl/maps/Xmovbsk1gBgScvbH8
One interesting thing about those Ontario meter lights is the placement. Usually limit-line meter signals (the standard in most places for single-lane meters) have an additional signal oriented towards the stop bar. These two signals seem like they would be harder to see when stopped at the limit line.
Georgia, for a 2-lane onramp, normally installs a mast arm and mounts the ramp meters on there. There are 2 overhead ramp meters for each lane because GA uses staggered release in those situations. Georgia did request an MUTCD interpretation from FHWA regarding the number and positioning of ramp meters for multi-lane onramps with staggered release; they have generally followed that interpretation. https://mutcd.fhwa.dot.gov/resources/interpretations/4_294.htm
https://goo.gl/maps/bgAEm5GX9BNu9i1E6
Quote from: ran4sh on June 18, 2021, 08:28:48 PM
Georgia, for a 2-lane onramp, normally installs a mast arm and mounts the ramp meters on there. There are 2 overhead ramp meters for each lane because GA uses staggered release in those situations. Georgia did request an MUTCD interpretation from FHWA regarding the number and positioning of ramp meters for multi-lane onramps with staggered release; they have generally followed that interpretation. https://mutcd.fhwa.dot.gov/resources/interpretations/4_294.htm
https://goo.gl/maps/bgAEm5GX9BNu9i1E6
Interesting... The official interpretation from MUTCD dates from 2005, and says a multi-lane ramp using staggered release should have two signal faces per lane.
However, the wording of the interpretation was not made a standard in the 2009 MUTCD. It requires only one overhead signal per lane (mounted over the center of the lane), although a guidance statement recommends considering a second, side-mounted signal head for each lane.
This makes Nevada's implementation of ramp meters more interesting. Nevada is a state that follows MUTCD standards closely and also usually implements most guidance statements, and also has side-mount redundancy at the vast majority of traditional traffic signals. Most of Nevada's ramp meters date from the era of 2009 MUTCD, and all of them date after the Interpretation. However, we use staggered release on all multi-lane ramp meters, but there are virtually no ramps with more than one signal per lane.
Quote from: ran4sh on June 18, 2021, 08:28:48 PM
Georgia, for a 2-lane onramp, normally installs a mast arm and mounts the ramp meters on there. There are 2 overhead ramp meters for each lane because GA uses staggered release in those situations. Georgia did request an MUTCD interpretation from FHWA regarding the number and positioning of ramp meters for multi-lane onramps with staggered release; they have generally followed that interpretation. https://mutcd.fhwa.dot.gov/resources/interpretations/4_294.htm
https://goo.gl/maps/bgAEm5GX9BNu9i1E6
Funnily enough, at the other onramp at that interchange, they seem to have changed it from two signals per lane to just one. Have a look the historical images here: https://goo.gl/maps/yjf3jrVzxBNgJNvGA (https://goo.gl/maps/yjf3jrVzxBNgJNvGA)
For an overseas perspective, the newly-installed meters here in Perth all use 8-8-8 signals.
(https://i.imgur.com/PEU3ZsP.png)
https://goo.gl/maps/MhXAubzraCK9w5fM8 (https://goo.gl/maps/MhXAubzraCK9w5fM8)
Interestingly, they have done their best to imitate US-style signals with some features not found at other traffic lights in Perth. For example, the ramp meters generally have far-side gantries with multiple signal faces, whereas at normal intersections, overhead signals are rare and are generally near-side with only one signal face.
Our ramp meters are also operated a bit differently. During metering, the signals go through the full G-Y-R but with a comically short yellow. Staggered starts are not used at all, so it is left to motorists to figure out who should go in front. Does anywhere in the US operate this way?
Quote from: Jet380 on June 19, 2021, 02:40:33 AM
Our ramp meters are also operated a bit differently. During metering, the signals go through the full G-Y-R but with a comically short yellow. Staggered starts are not used at all, so it is left to motorists to figure out who should go in front. Does anywhere in the US operate this way?
in colorado, it's a drag race. usually (but not always) the two lanes narrow to one before meeting the freeway
Quote from: roadfro on June 19, 2021, 01:49:35 AM
Nevada is a state that follows MUTCD standards closely and also usually implements most guidance statements, and also has side-mount redundancy at the vast majority of traditional traffic signals. Most of Nevada's ramp meters date from the era of 2009 MUTCD, and all of them date after the Interpretation. However, we use staggered release on all multi-lane ramp meters, but there are virtually no ramps with more than one signal per lane.
Certain districts of California also use the overhead-only, one-per-lane strategy similar to Nevada and Washington State.
Example in San Jose (https://goo.gl/maps/yM3k1uauvzsqWVuq7) like that. Very odd, since California is normally quite mental about two signals per movement. Down in Southern California, however, it seems to be the norm to use post-mounted signals whenever physically possible (so you get odd things like
this (https://goo.gl/maps/AQPPFct2LmcpPk7r7) and
this (https://goo.gl/maps/9FzJd7sNBm3ntpteA), but normally everything is like
this (https://goo.gl/maps/FPJu82m2GmRVGzNC8) (similar to WSDOT's
alternate style (https://goo.gl/maps/sGxUtKRk8X9pYCnh6)).
Quote from: ran4sh on June 18, 2021, 08:28:48 PM
Georgia, for a 2-lane onramp, normally installs a mast arm and mounts the ramp meters on there. There are 2 overhead ramp meters for each lane because GA uses staggered release in those situations. Georgia did request an MUTCD interpretation from FHWA regarding the number and positioning of ramp meters for multi-lane onramps with staggered release; they have generally followed that interpretation. https://mutcd.fhwa.dot.gov/resources/interpretations/4_294.htm
https://goo.gl/maps/bgAEm5GX9BNu9i1E6
Has Georgia not heard of a post or pedestal? The best time to use them is at ramp meters, and they still refuse to use them (that MUTCD question indicates some concern about mixing overhead and post-mounted signals ... based on what evidence?). In fact, I cannot recall ever seeing a post-mounted signal in George. Do they even exist anywhere? Apart from DDIs or other offset intersections.
^^ Here is one in Atlanta (single lane): https://goo.gl/maps/ABVaJtkippcjx9ft6
I don't usually defend GDOT but I'll do it here. Why would it be appropriate to use a post mounted signal for a 2-lane ramp, unless the post is all the way off the shoulder (which would reduce its conspicuousness). The overhead mast arm, with the pole being far enough off the shoulder and protected with guardrail, seems to be the ideal ramp meter setup.
(I'm actually not in favor of ramp meters at all, they're a symptom of failing to provide enough transportation capacity. [they only exist because they're cheaper than actually reducing congestion and/or increasing capacity])
Quote from: ran4sh(I'm actually not in favor of ramp meters at all, they're a symptom of failing to provide enough transportation capacity. [they only exist because they're cheaper than actually reducing congestion and/or increasing capacity])
That is
not the only reason they exist. They provide significant benefits in terms of both crash reduction and flow stability, at a rate far greater than your "increasing capacity" would.
Basically, ramp meters are intended to use the same amount of capacity more efficiently, increasing the number of vehicles that can pass through the same number of lanes. Sort of like replacing an incandescent bulb with a brighter LED light; you're getting more of what you want in the same space and cost footprint as the original.
Quote from: ran4sh on June 19, 2021, 04:58:31 PM
I don't usually defend GDOT but I'll do it here. Why would it be appropriate to use a post mounted signal for a 2-lane ramp, unless the post is all the way off the shoulder (which would reduce its conspicuousness). The overhead mast arm, with the pole being far enough off the shoulder and protected with guardrail, seems to be the ideal ramp meter setup.
My primary issue with overhead
only ramp meter signals is that they are inconspicuous when the sun is behind them. This is an issue with all signals, but is more apparent with ramp meters as they are typically active only during sun-up and sun-down times. As ramps are also quite often angled up or down, this can sometimes mean the roadway geometry exacerbates the issue even further (positive-angle on-ramps are pointing up towards a rising or setting sun).
Using two signals per lane, but all overhead (the first GA example), also means you are placing the signals too close together under MUTCD rules (less than eight feet); this then requires additional signage to indicate which signals belong to which lane.
Good setups, by comparison, are in places like
Californi (https://goo.gl/maps/FPJu82m2GmRVGzNC8)a and
Washington (https://goo.gl/maps/sGxUtKRk8X9pYCnh6): signals are in the shoulder, closer to eye level and thus you are not being blinded; there is redundancy; it is very clear which signal is for which lane simply by the placement of the signals (left or right side of the roadway). Three-lane meters obviously need overhead signals, but you can still supplement the outside lanes with post-mounted signals. Or just
bulb-out (https://goo.gl/maps/orELCvdygvt5y4Cq7) one side!
For the record, I am not aware of any outstanding issues regarding signal mast/signal pole conspicuity in terms of them being hit. I assume this concern is rooted in the idea that pole-mounted signals are more prevalent to being knocked down. This isn't false, per se, but I don't believe it's an issue with ramp meter signals. Keep in mind that pole-mounted ramp meter signals are by far the most common setup in the US, and I doubt this would be the case if they were regularly knocked down.
Quote from: jakeroot on June 19, 2021, 10:00:14 PM
My primary issue with overhead only ramp meter signals is that they are inconspicuous when the sun is behind them. This is an issue with all signals, but is more apparent with ramp meters as they are typically active only during sun-up and sun-down times.
That depends very highly on the latitude and time of year. In Norman, sunrise today was at 6:15 am and sunset at 8:47 pm, far outside of the normal rush periods. Sunrise and sunset coinciding with peak demand periods really only happens here around the winter solstice.
Quote from: Scott5114 on June 19, 2021, 10:09:22 PM
Quote from: jakeroot on June 19, 2021, 10:00:14 PM
My primary issue with overhead only ramp meter signals is that they are inconspicuous when the sun is behind them. This is an issue with all signals, but is more apparent with ramp meters as they are typically active only during sun-up and sun-down times.
That depends very highly on the latitude and time of year. In Norman, sunrise today was at 6:15 am and sunset at 8:47 pm, far outside of the normal rush periods. Sunrise and sunset coinciding with peak demand periods really only happens here around the winter solstice.
It's not
just sunset and sunrise, but also the period leading up to/following it (respectively). The sun can be way up in the sky when you first enter the on-ramp, and then right behind the signal by the time you reach the limit line.
Here in Seattle, morning rush is (guessing here) 5am to 9am, and evening rush from 2pm to 7pm. Sunset and sunrise (and the period leading up to/following it!) are factors basically year-round for at least some drivers.
I suppose if the rush is that long, you have a greater chance of sun placement being a problem for at least part of it. Here, evening rush doesn't start until 5pm and is normally cleared out by 6pm.
Quote from: Scott5114 on June 20, 2021, 12:14:22 AM
I suppose if the rush is that long, you have a greater chance of sun placement being a problem for at least part of it. Here, evening rush doesn't start until 5pm and is normally cleared out by 6pm.
I shall also imagine that an area with a rush that short likely either doesn't have meters nor need them.
To think peak-hour could be less than an actual hour ... :-D
Sun location doesn't seem to be a problem for most Atlanta ramp meters, which might be why no one here even thinks of it. I-75 and 400 are mostly north/south, and I-85 on the NE side, while it's close to east/west, commuters are generally facing away from the sun. That leaves I-20 on the west side and I-285's east/west sections as the only freeways in the area where this would be a problem during the normal commute.
Quote from: jakeroot on June 19, 2021, 01:08:34 PM
Quote from: ran4sh on June 18, 2021, 08:28:48 PM
Georgia, for a 2-lane onramp, normally installs a mast arm and mounts the ramp meters on there. There are 2 overhead ramp meters for each lane because GA uses staggered release in those situations. Georgia did request an MUTCD interpretation from FHWA regarding the number and positioning of ramp meters for multi-lane onramps with staggered release; they have generally followed that interpretation. https://mutcd.fhwa.dot.gov/resources/interpretations/4_294.htm
https://goo.gl/maps/bgAEm5GX9BNu9i1E6
Has Georgia not heard of a post or pedestal? The best time to use them is at ramp meters, and they still refuse to use them (that MUTCD question indicates some concern about mixing overhead and post-mounted signals ... based on what evidence?). In fact, I cannot recall ever seeing a post-mounted signal in George. Do they even exist anywhere? Apart from DDIs or other offset intersections.
I agree. I think having 4 separate overhead signal faces as is done in Georgia would be somewhat confusing. I think the Australian way (as pictured in one of the above comments) is far more intuitive. One overhead and one side signal face for each lane. Alternatively, having pedestal only (where both of the pedestals have two signal faces) would be another possibility. Indeed the FHWA guidance suggests that using pedestals with both a low singal face and a high signal face is common and a good application for staggered release.